Circulating tumor cells (CTCs) are tumor cells that are shed into the blood stream by a solid tumor such as prostate cancer. Current data supports CTCs likely denote the more aggressive tumor cells that have metastatic potential. It is extremely challenging to identify CTCs in context of 10^8 excess white blood cells in peripheral blood. The use of advanced microfluidic chip-based CTC detection method, such as the Nano-Velcro chip used in this project, has been shown to exhibit greatly enhanced CTC capture efficiency in prostate cancer patients, providing an earlier and more sensitive readout of treatment response than the FDA approved CellSearch(trade mark) CTC detection method, serum PSA or radiographic CT assessment. However, a limitation of the current detection technology is its inability to assess dynamic functional activity, such as the AR pathway, in the living CTCs as the immunohistochemistry approach of current methods can only provide static protein expression in the CTCs. This DOD funded project aims to incorporate the use of AR-driven reporter recombinant vectors to query dynamic AR functional status in viable CTCs captured by the Nano-Velcro chip.